The present invention relates to extracting data from compressed data. More specifically, the invention relates to data decompression for a random location within a compressed data block.
Data compression is the process of transforming information from a first representation to a second representation, with the second representation being smaller than the first representation (also known as the original representation). Compressed data may be decompressed from which the original, or a close approximation to it, can be recovered. Compression and decompression processes are often referred to as encoding and decoding. Data compression has important applications in the areas of data storage and data transmission. Besides space savings, other parameters of concern include encoding and decoding speeds and workspace requirements, the ability to access and decode partial files, and error generation and propagation.
The data compression process is said to be lossless if the recovered data are assured to be identical to the source; otherwise the compression process is said to be lossy. Lossless compression techniques are required for applications involving textual data. Other applications, such as those involving voice and image data, may be sufficiently flexible to allow controlled degradation in the data.